Google created supplemental index in order to optimize crawling and indexing the web. Web pages that were found to be poor in content, not relevant by having too few or duplicate content were put in this “graveyard” of web pages. Once there, they were marked as not relevant to appear in Goolgle SERPs (Search Engine Result Pages). They were destined to be crawled at a lower frequency compared to pages not being in Supplemental Index.

Some time ago Google announced that Supplemental Index label was dropped since the crawling and indexing web sites, however, the experience shows the opposite.

How can I know that my pages are in Supplemental Index?

If you notice that your website traffic coming from organic searches in Google drops down, it is a sign that some of your pages are “supplemental”. To confirm this, take, for example, a part of the content from the page in question containing the end of one sentence and the beginning of the the next one, a combination of words that is not very likely to appear in the exact order on any other web page, (e.g. “and indexing the web. Web pages that were found” from the first and second sentence of this article) and perform the search in Google. If you find other web pages in front of yours, it is a sure sign that your web page is in Supplemental Index.

How can I find all the pages that are in Supplemental Index?

There were a number of ways, but the one I found is working right now is the following:

- Perform the following search to find all the pagesof your website indexed by Google (replacing example.com with your domain)

site:www.example.com

- Perform the following search to find all the web pages that are NOT in Google Supplemental Index (again, replacing example.com with your own domain)

site:www.example.com//

Simply, the difference between the two searches will show you all pages that currently are in Google Supplemental Index and are not likely to appear in the search results as you might have expected.

In next post I will write about how to get your pages out of Google Supplemental Index. It will be the experiment I will perform on this very site.

Filed under: search engine optimization.